The present invention relates to the field of driving assistance, and in particular to starting the vehicle or setting it in motion.
The estimate of the clutch curve, or more precisely of a mapping of the torque transmitted by a clutch fitted to a motor vehicle, can be of use to various systems on board a motor vehicle, and in particular to a system for assisting a hill start of a motor vehicle.
French patent application number 2 828 450 (Renault) relates to a hill-start assistance device for a motor vehicle. The assistance device comprises mainly a means for estimating a slope on which the vehicle is positioned, a means for interpreting the actions of the driver, a means for determining a characteristic curve of the clutch of the vehicle and a means for automatically deactivating a braking means of the vehicle. The motor vehicle can thus be held in position on a slope in a state in which the drive wheels are disengaged from the engine, and can be set in motion in the upslope direction only by the actions of the driver on the accelerator and clutch pedals, without the driver having to act on the parking brake. The assistance device controls the release of the brakes as soon as the torque transmitted to the wheels is sufficient to compensate for the force on the vehicle due to the slope and to gravity.
The mapping of the torque transmitted by a clutch fitted to a motor vehicle is, in a conventional manner, updated, when the vehicle is in motion, by means of predetermined and invariable position thresholds.
Therefore, an incorrect predetermination of these thresholds can cause an incorrect update, and even an absence of an update, of the mapping of the torque transmitted by the clutch.
Moreover, it is possible that the predetermined thresholds are suitable for updating the mapping when the clutch is new, but become unsuitable after a certain degree of wear of the clutch.